win: Add memory map range intersection helper

util/win/process_info.h

Index: util/win/process_info.h
diff --git a/util/win/process_info.h b/util/win/process_info.h
index 5af28bd762bddabcc62f2f8be5e7cb88150f7ff0..58b10135669dbfa47b8d837ac521390a292fef52 100644
--- a/util/win/process_info.h
+++ b/util/win/process_info.h
@@ -23,6 +23,7 @@
 
 #include "base/basictypes.h"
 #include "util/misc/initialization_state_dcheck.h"
+#include "util/numeric/checked_range.h"
 #include "util/win/address_types.h"
 
 namespace crashpad {
@@ -52,6 +53,7 @@ class ProcessInfo {
   // \brief Contains information about a range of pages in the virtual address
   //    space of a process.
   struct MemoryInfo {
+    MemoryInfo();

[Mark Mentovai, 2015/10/01 17:38:59]

We killed this in
https://codereview.chromium.org/1369833002/diff/60001/util/win/process_info.h....
Since it’s only used in the test, maybe it’d be better to debloat by not having
this and instead moving the bloat to the test by building MemoryInfo objects
from MEMORY_BASIC_INFORMATION.

[scottmg, 2015/10/01 18:10:02]

Done.

     explicit MemoryInfo(const MEMORY_BASIC_INFORMATION& mbi);
     ~MemoryInfo();
 
@@ -129,6 +131,16 @@ class ProcessInfo {
   //! \brief Retrieves information about all pages mapped into the process.
   const std::vector<MemoryInfo>& MemoryInformation() const;
 
+  //! \brief Given a range to be read from the target process, returns a vector
+  //!     of ranges, representing the readable portions of the original range.
+  //!
+  //! \param[in] range The range being identified.
+  //!
+  //! \return A vector of ranges corresponding to the portion of the range
+  //!     identified by \a range that are readable, based on the memory map.
+  std::vector<CheckedRange<WinVMAddress, WinVMSize>> GetReadableRanges(
+      const CheckedRange<WinVMAddress, WinVMSize>& range) const;
+
  private:
   template <class Traits>
   friend bool GetProcessBasicInformation(HANDLE process,
@@ -157,6 +169,18 @@ class ProcessInfo {
   DISALLOW_COPY_AND_ASSIGN(ProcessInfo);
 };
 
+//! \brief Given a memory map of a process, and a range to be read from the
+//!     target process, returns a vector of ranges, representing the readable
+//!     portions of the original range.
+//!
+//! This is a free function for testing, but prefer
+//! ProcessInfo::GetReadableRanges().
+//!
+//! \sa ProcessInfo::GetReadableRanges()

[Mark Mentovai, 2015/10/01 17:38:59]

I don’t think you need to say \sa when you just gave the name of the alternative
in full above.

[scottmg, 2015/10/01 18:10:02]

Done.

+std::vector<CheckedRange<WinVMAddress, WinVMSize>> GetReadableRangesOfMemoryMap(
+    const CheckedRange<WinVMAddress, WinVMSize>& range,
+    const std::vector<ProcessInfo::MemoryInfo>& memory_info);
+
 }  // namespace crashpad
 
 #endif  // CRASHPAD_UTIL_WIN_PROCESS_INFO_H_